The Sylmar Quake was no fun either. We lived in Granada Hills, near Van Norman Dam. They thought it would break so everyone was told to leave their homes that night. Our family stayed in our house because we were to the west off Rinaldi Blvd. high enough so water would'nt get to it. But it was very strange...No power and helicopters flying over all night long....a lot of damage to the house.
I have friends that live probably fairly close to where your family was located. I remember going up there to see if I could help clean up their house.
When those helicopters fly overhead, the least they could do is squawk through their loudspeakers what or who they are looking for and what, if anything they see.